KR100612363B1 - A polymer membrane for fuel cell, method for preparing thereof, and fuel cell system comprising the same - Google Patents

Abstract

The present invention relates to a fuel cell polymer membrane, a method for manufacturing the same, and a fuel cell system including the same, wherein the polymer membrane has a molecular weight of 30,000 to 70,000 poly [2,2 ′-(m-phenylene) -5,5 VII-bibenzimidazole] Provided is a polymer membrane for a fuel cell containing a polymer. The polymer membrane is condensed by adding a 3,3′-diaminobenzidine monomer, an isophthalic acid monomer, and a dehydrating agent comprising P ₂ O ₅ and CH ₃ SO ₃ H to the reactor; It is prepared by a process of adding an excess of P ₂ O ₅ to the reaction tank during the condensation reaction of the monomer.

Fuel Cell, P2O5

Description

Polymer membrane for fuel cell, manufacturing method thereof, and fuel cell system including same {A POLYMER MEMBRANE FOR FUEL CELL, METHOD FOR PREPARING THEREOF, AND FUEL CELL SYSTEM COMPRISING THE SAME}

1 is a cross-sectional view schematically showing an operating state of a fuel cell including a polymer electrolyte membrane.

<Description of the symbols for the main parts of the drawings>

1: fuel cell 10a: anode catalyst layer (anode electrode)

10b: air cathode catalyst layer (cathode electrode) 15: polymer electrolyte membrane

20: membrane / electrode assembly

[Industrial use]

The present invention relates to a polymer membrane for a fuel cell, a method for manufacturing the same, and a fuel cell system including the same. More specifically, a polymer having a wide molecular weight range can be prepared, and trifluoromethanesulphonic acid, which is harmful to a human body, is used when preparing a polymer membrane. The present invention relates to a polymer membrane for a fuel cell, which is not harmful to the environment, a manufacturing method thereof, and a fuel cell system including the same.

[Prior art]

A fuel cell is a power generation system that directly converts the chemical reaction energy of hydrogen and oxygen contained in hydrocarbon-based materials such as methanol, ethanol and natural gas into electrical energy.

Fuel cells are classified into phosphoric acid fuel cells, molten carbonate fuel cells, solid oxide fuel cells, polymer electrolyte batteries, or alkaline fuel cells according to the type of electrolyte used. Each of these fuel cells operates on essentially the same principle, but differs in the type of fuel used, operating temperature, catalyst, and electrolyte.

Among these, polymer electrolyte fuel cells (PEMFCs), which are being developed recently, have much higher output characteristics, lower operating temperatures, faster start-up and pressure characteristics than other fuel cells, As well as transportable power supply, there is a wide range of applications such as distributed power supply such as homes, public buildings and small power supply such as for electronic devices.

The polymer electrolyte fuel cell as described above basically includes a stack, a reformer, a fuel tank, a fuel pump, and the like to construct a system. The stack forms the body of the fuel cell, and the fuel pump supplies the fuel in the fuel tank to the reformer. The reformer reforms the fuel to generate hydrogen gas and supplies the hydrogen gas to the stack. Accordingly, the polymer electrolyte fuel cell supplies fuel in a fuel tank to a reformer by operation of a fuel pump, reforming the fuel in the reformer to generate hydrogen gas, and electrochemically react the hydrogen gas and oxygen in a stack. To generate electrical energy.

On the other hand, the fuel cell may employ a direct methanol fuel cell (DMFC) method that can supply a liquid methanol fuel directly to the stack. Such a direct methanol fuel cell fuel cell, unlike the polymer electrolyte fuel cell, the reformer is excluded.

In such a fuel cell system, a stack that substantially generates electricity is composed of a number of unit cells consisting of a membrane / electrode assembly (MEA) and a separator (also called a bipolar plate). It has a stacked structure of several tens. The membrane / electrode assembly has a structure in which an anode electrode (also called "fuel electrode" or "oxide electrode") and a cathode electrode (also called "air electrode" or "reduction electrode") are attached with a polymer electrolyte membrane interposed therebetween. Have

In this case, the polymer membrane / electrode assembly includes a solid polymer electrolyte membrane and a carbon supported catalyst electrode layer. Examples of the polymer electrolyte membrane that serves as the electrolyte include Nafion (trade name of Nafion, manufactured by DuPont), Premion (trade name of manufactured by Asahi Glass), Asifrex (trade name of manufactured by Asahi Chemical), and Dow A perfluorosulfonate ionomer membrane such as XUS (Dow XUS, Dow Chemical Co., Ltd.) electrolyte membrane is widely used. The carbon-supported catalyst electrode layer combines a carbon powder carrying fine catalyst particles such as platinum (Pt) or ruthenium (Ru) with a waterproof binder on an electrode support such as porous carbon paper or carbon cloth. I'm using it.

On the other hand, in recent years, [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymers have been used as polymer films for fuel cells.

The [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer generally comprises monomers as P ₂ O ₅ , CF ₃ SO ₃ H, CH ₃ SO ₃ H It is prepared by the condensation reaction by adding a dehydrating agent such as. By the condensation reaction, phosphoric acid is produced by the reaction of water with P ₂ O ₅ used as a dehydrating agent, as shown in Scheme 1 below, at which time the two water molecules escape, polybenzimidazole polymer is produced.

Scheme 1

2P ₂ O ₅ + 6H ₂ O → 4H ₃ PO ₄

However, in order to obtain a higher molecular weight polymer among the dehydrating agents, trifluoromethanesulphonic acid (CF ₃ SO ₃ H) having a pKa of about -10 is used rather than CH ₃ SO ₃ H having a pKa of about -2. . When the trifluoromethanesulphonic acid is used above, the poly [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer has a molecular weight range of 40,000 to 50,000. Is being manufactured.

However, the trifluoromethanesulphonic acid (CF ₃ SO ₃ H) is very toxic, harmful to humans and expensive and may cause economic problems.

In order to solve the above problems in the prior art, an object of the present invention is a polymer membrane for fuel cells that has a wider molecular weight range and is not harmful to the environment compared to the prior art without using trifluoromethane sulfonic acid, which is harmful to the human body and is extremely toxic. In order to provide a method for manufacturing the same and a fuel cell system including the same.

In order to achieve the above object, the present invention provides a polymer membrane for a fuel cell comprising a poly [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] polymer having a molecular weight of 30,000 to 70,000. To provide.

The present invention also provides a condensation reaction of a 3,3′-diaminobenzidine monomer, an isophthalic acid monomer, and a dehydrating agent comprising P ₂ O ₅ and CH ₃ SO ₃ H to a reaction tank; It provides a method for producing a polymer film for a fuel cell prepared by the step of adding an excess of P ₂ O ₅ to the reaction tank during the condensation reaction of the monomer.

The present invention also includes a catalyst layer formed by coating a catalyst slurry on one surface of an electrode support, wherein the catalyst slurry is [2,2 '-(m-phenylene) -5,5'-bibenz prepared by the above method. It provides an electrode for a fuel cell comprising an imidazole] (PBI) polymer, and a metal catalyst supported on carbon.

The present invention also provides an anode electrode and a cathode electrode located opposite each other, and a molecular weight range of 30,000 to 70,000 [2,2 '-(m-phenylene) -5,5' positioned between the anode electrode and the cathode electrode. A membrane / electrode assembly comprising a polymer membrane comprising a bibenzimidazole] (PBI) polymer; And a separator for sandwiching the membrane / electrode assembly, the at least one electricity generating unit generating electricity through an electrochemical reaction between hydrogen and oxygen; A fuel supply unit supplying hydrogen to the electricity generation unit; And an oxygen supply unit supplying oxygen to the electricity generation unit.

The invention also relates to anode and cathode electrodes located opposite each other, and [2,2 '-(m-phenylene) -5,5'-by, prepared according to the method located between the anode and cathode electrodes. A membrane / electrode assembly comprising a polymer membrane comprising benzimidazole] (PBI) polymer; And a separator for sandwiching the membrane / electrode assembly, the at least one electricity generating unit generating electricity through an electrochemical reaction between hydrogen and oxygen; A fuel supply unit supplying hydrogen to the electricity generation unit; And an oxygen supply unit supplying oxygen to the electricity generation unit.

Hereinafter, the present invention will be described in more detail.

The present invention provides an excess of P ₂ O ₅ , which is used as a dehydrating agent in the production of [2,2 ′-(m-phenylene) -5,5′-bibenzimidazole] (PBI) polymer, A polymer membrane having a large molecular weight range can be provided. In addition, the present invention does not use trifluoromethanesulphonic acid (CF ₃ SO ₃ H), which is very toxic when preparing a polymer, and thus is not harmful to the environment. In addition, by using excessively P ₂ O ₅ , ion conductivity was greatly improved.

The poly [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer of the present invention is represented by the following formula (1).

[Formula 1]

In the formula, n represents the degree of polymerization and is an integer of 150 to 300.

The poly [2,2 ′-(m-phenylene) -5,5′-bibenzimidazole] (PBI) polymer may be a 3,3′-diaminobenzidine monomer or an isophthalic acid monomer, and P ₂ O ₅ And a dehydrating agent comprising CH ₃ SO ₃ H can be prepared by the condensation reaction by addition to the reactor.

At this time, the present invention can increase the molecular weight range of the polymer in the step of adding the excess of P ₂ O ₅ used as a dehydrating agent in the reaction tank during the condensation reaction of the monomer. In addition, the present invention is environmentally friendly using CH ₃ SO ₃ H having a pka of about -2 without using a highly toxic trifluoromethanesulphonic acid (CF ₃ SO ₃ H) in the condensation reaction. The amount of P ₂ O ₅ is preferably added in a molar ratio of 5 to 7 times with respect to the 3,3'-diaminobenzidine monomer.

In addition, the 3,3'-diaminobenzidine and isophthalic acid are preferably used in precise molar ratios.

By this process, the present invention can produce poly [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) having a molecular weight range of 30,000 to 70,000.

The polycondensation reaction is preferably made for 30 minutes to 1 hour at a temperature of 160 ℃ to 170 ℃. In addition, the polycondensation reaction may be carried out in a nitrogen atmosphere or vacuum, water generated by the polycondensation reaction can be removed by using a device such as Dean Stark installed separately connected to the reactor.

In the present invention, when the condensation polymerization, a dehumidifying agent such as silica gel can be used.

[2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer having a wide molecular weight range prepared in the present invention is included in the anode electrode and the cathode electrode catalyst layer to form an electrode and an electrolyte membrane. Improves adhesion. Therefore, according to the present invention, at least one of the anode electrode, the cathode electrode and the polymer electrolyte may be prepared by using the [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer. It can be firmly attached by reducing the interface resistance that can be generated at the electrode and the polymer electrolyte membrane interface.

The present invention may be prepared by dissolving the [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer in an organic solvent, then casting it on a substrate and drying it.

In addition, the present invention can produce a fuel cell electrode using a [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer having a wide molecular weight range prepared above. have. The present invention provides a fuel cell electrode comprising a catalyst layer by coating a catalyst slurry on one surface of an electrode support, wherein the catalyst slurry is [2,2 범위-(m-phenylene) -5 having a wide molecular weight range of the present invention. , 5′-bibenzimidazole] (PBI) polymer, and a metal catalyst supported on carbon.

The catalyst layer of the electrode may include a PBI polymer of the present invention to obtain an electrode for a fuel cell having an ion conductivity of 0.06 S / cm to 0.08 S / cm.

[2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer in the catalyst slurry does not exist in a dissolved state but exists in a dispersed state. The coating process may be a screen printing method, a spray coating method or a coating method using a doctor blade according to the viscosity of the dispersion, but is not limited thereto.

The electrode support serves as a gas diffusion layer, which serves to support the fuel cell electrode, and diffuses the reaction gas into the catalyst layer, thereby easily accessing the reaction gas to the catalyst layer. The gas diffusion layer may be carbon paper or carbon cloth, but is not limited thereto. In addition, the gas diffusion layer using a water-repellent treatment of carbon paper or carbon cloth with a fluorine-based resin such as polytetrafluoroethylene can prevent the gas diffusion efficiency from being lowered by water generated when the fuel cell is driven. desirable.

In the electrode of the present invention, the catalyst layer includes a so-called metal catalyst which catalyzes the related reactions (oxidation of hydrogen and reduction of oxygen), and includes a platinum group metal of the periodic table of elements, for example, Pt or Ru, transitions such as Fe or Co Metals and the like can be used. Also generally, those supported on a carrier are used. As the carrier, carbon such as acetylene black or graphite may be used, or inorganic fine particles such as alumina or silica may be used. In the case of using the noble metal supported on the carrier as a catalyst, a commercially available commercially available product may be used, or the noble metal supported on the carrier may be prepared and used. Since the process of supporting the precious metal on the carrier is well known in the art, detailed descriptions thereof will be readily understood by those skilled in the art even if the detailed description is omitted. The metal catalyst used in the present invention is preferably selected from the group consisting of Pt, Pt / Ru, and Pt / Fe / Co.

The present invention can also provide a membrane / electrode assembly using the [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] (PBI) polymer. The membrane / electrode assembly is formed by placing a polymer electrolyte membrane between an anode electrode and a cathode electrode disposed to face each other, firing them, and then hot rolling. At this time, any one of the anode electrode and the cathode electrode comprises an electrode according to the above method, the polymer electrolyte membrane has a molecular weight range of 30,000 to 70,000 [2,2 ′-(m-phenylene) -5 of the present invention , 5′-bibenzimidazole] (PBI) polymer can be used.

The polymer electrolyte membrane may include a conventional hydrogen ion conductive polymer in addition to the polymer of the present invention, which is three-dimensionally connected inside the micropores to form an ion transport path. The hydrogen ion conductive polymer may be used as long as it has hydrogen ion conductivity. For example, a perfluoro polymer, a ketone polymer, a polyether polymer, a polyester polymer, a polyamide polymer, a polyimide polymer, or the like. This can be used. Specific examples of the hydrogen ion conductive polymer include poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), Tetrafluoroethylene and fluorovinyl ether copolymers containing sulfonic acid groups, defluorinated sulfide polyether ketones, aryl ketones, and the like may be used, but are not limited thereto.

In addition, the present invention provides an electricity generating unit having at least one unit cell manufactured by inserting the membrane / electrode assembly between the gas flow channel and the separator (or bipolar plate) formed with a cooling channel, supplying hydrogen to the electricity generating unit It provides a fuel cell system including a fuel supply unit and an oxygen supply unit for supplying oxygen to the electricity generating unit.

The electricity generator serves to generate electricity through an electrochemical reaction of hydrogen and oxygen. The fuel supply unit serves to supply fuel containing hydrogen to the electricity generator, and the oxygen supply unit serves to supply oxygen to the electricity generator.

1 is a view schematically showing an operating state of a fuel cell 1 including a membrane / electrode assembly 20. In the fuel cell 1, the membrane / electrode assembly 20 includes an anode electrode 10a serving as an anode catalyst layer, a cathode electrode 10b serving as an anode catalyst layer, and a polymer electrolyte membrane 15. Referring to FIG. 1, when a fuel supply source including a hydrogen gas is supplied to the anode catalyst layer 10a, an electrochemical oxidation reaction occurs and ionizes to hydrogen ions H ⁺ and electrons e ⁻ . The ionized hydrogen ions move to the cathode catalyst layer 10b by the oxygen source through the polymer electrolyte membrane 15 and electrons move through the anode catalyst layer 10a. Hydrogen ions transferred to the cathode catalyst layer 10b cause an electrochemical reduction reaction with oxygen supplied to the cathode catalyst layer 10b to generate heat of reaction and water, and electrical energy is generated by the movement of electrons. This electrochemical reaction can be represented by the following scheme.

Scheme 2

The ^{_{anode: H 2 → 2H + + 2e}} -

_{^{Cathode: 2H + + 1/2 O 2 +}} 2e - → H 2 O

The electricity generating unit includes a stack in which unit cells are stacked, and a stack may be inserted between two end plates to manufacture a fuel cell, and the fuel cell may be all manufactured by conventional techniques in the art. The membrane / electrode assembly of the present invention can be applied to both low temperature humidification type, low temperature no humidification type, and high temperature no humidification type batteries.

In addition, in the fuel cell system of the present invention, the fuel supply source includes a fuel containing hydrogen and may include water. The hydrogen-containing fuel and water reform the fluid by vaporization to generate hydrogen gas, which is done through the reformer. Thus, the present invention supplies a fuel supply to the reformer.

The reformer may include a heat path having a predetermined length through which the mixed fuel passes, a catalyst layer formed on an inner surface of the flow path, and supplying a heat source for vaporizing the mixed fuel; And a flow path having a predetermined length through which the mixed fuel passes, and a catalyst layer is formed on an inner surface of the flow path, and includes a reforming reaction unit generating hydrogen gas from the mixed fuel through a chemical catalytic reaction by the heat source.

In addition, the fuel cell system of the present invention may include at least one carbon monoxide reduction unit for reducing the concentration of carbon monoxide contained in the reformed hydrogen gas.

In the fuel cell system according to the present invention, the flow path of the reformer has an inlet through which the fuel introduced from the fuel supply is introduced, and an outlet through which the reformed gas generated through the reforming reaction flows out.

The heat source unit may further include a heating member installed in contact with the flow path to heat the flow path, the heating member may include a heating plate in contact with the flow path, and a heating wire embedded in the heating plate. It is preferable to form a joining groove for joining the flow path in the heating plate. In this case, the flow path may be formed to be bent in a zigzag shape.

The flow path formed inside the combustion reactor included in the heat source part may be formed by a conventional method, and a support layer may be disposed between the inner surface of the flow path and the catalyst layer to support the catalyst layer. As the catalyst of the heat source unit, precious metals such as Pt / Ru may be mainly used, but are not particularly limited thereto.

In addition, the reforming reaction unit may include a flow path formed by a conventional method therein, and an inner surface of the flow path may include a support layer and a catalyst layer. Zn, Fe, Cr, Cu, Ni, Rh, Cu / Zn and the like may be mainly used as the catalyst of the reforming unit, but is not particularly limited.

The shape of the reformer including the heat source portion and the reforming reaction portion may be a substantially rectangular or circular tube having a predetermined length, width and thickness, and the form is not particularly limited. The present invention can complete the reformer for a fuel cell by welding and integrating the heat source portion and the reforming reaction portion together.

Further, in the fuel cell system according to the present invention, the fuel supply source is connected to a first tank for storing a liquid fuel containing hydrogen, a second tank for storing water, and the first and second tanks. It includes a fuel pump is installed, the air supply may include an air pump for sucking the outside air.

In addition, the present invention includes an air supply source for supplying external air to the electricity generating unit. The fuel cell system of the present invention may use pure oxygen gas stored in a separate storage means as oxygen reacting with hydrogen contained in the fuel, or may use air containing oxygen as it is.

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only one preferred embodiment of the present invention and the present invention is not limited to the following examples.

(Example 1)

2.42 g of 3,3′-diaminobenzidine monomer, 1.88 g of isophthalic acid monomer, 7 g of P ₂ O ₅ , and 30 ml of CH ₃ SO ₃ H were added to the reactor to carry out the condensation reaction. At this time, a poly [2,2 '-(m-phenylene) -5,5-bibenzimidazole) having a molecular weight of 30,000 was prepared by further adding an excessive amount of P ₂ O ₅ 2 g during the condensation reaction. It was.

(Example 2)

2.42 g of 3,3′-diaminobenzidine monomer, 1.88 g of isophthalic acid monomer, 7 g of P ₂ O ₅ , and 30 ml of CH ₃ SO ₃ H were added to the reactor to carry out the condensation reaction. At this time, a poly [2,2 '-(m-phenylene) -5,5-bibenzimidazole) having a molecular weight of 50,000 was prepared by further adding an excessive amount of 4.5 g of P ₂ O ₅ during the condensation reaction. It was.

(Example 3)

2.42 g of 3,3′-diaminobenzidine monomer, 1.88 g of isophthalic acid monomer, 7 g of P ₂ O ₅ , and 30 ml of CH ₃ SO ₃ H were added to the reactor to carry out the condensation reaction. At this time, a poly [2,2 '-(m-phenylene) -5,5-bibenzimidazole) having a molecular weight of 70,000 was prepared by further adding an excessive amount of P ₂ O ₅ 8 g during the condensation reaction. It was.

(Example 4)

1 g of poly [2,2 '-(m-phenylene) -5,5-bibenzimidazole) prepared in Example 1 was added to 10 g of DMAc and 3 g of Pt / C were mixed to prepare a catalyst slurry. After the preparation, it was coated on a water repellent treated carbon paper to prepare an electrode including a catalyst layer, respectively.

The electrode prepared above was used as an anode electrode and a gain electrode, and the poly [2,2 '-(m-phenylene) -5,5-bibenzimidazole) polymer of Example 1 was used as an electrolyte membrane. The anode electrode and the cathode electrode were laminated on both surfaces thereof and then pressurized to prepare a membrane / electrode assembly.

The prepared membrane / electrode assembly is inserted between two gaskets, and then inserted into two separators (or bipolar plates) in which a gas channel and a cooling channel of a predetermined shape are formed, and then between the copper end plates. It was compressed in the unit cell was prepared.

(Comparative Example 1)

A fuel cell was manufactured in the same manner as in Example 1, but CF ₃ SO ₃ H was used instead of CH ₃ SO ₃ H as a dehydrating agent during the condensation reaction. The poly [2,2 '-(m-phenylene) -5,5-bibenzimidazole) thus prepared had a molecular weight of 100,000.

(Comparative Example 2)

Prepared in the same manner as in Example 1, but did not add P ₂ O ₅ during the condensation reaction. In this case, poly [2,2 '-(m-phenylene) -5,5-bibenzimidazole) was not well synthesized.

Experimental Example

For Example 1 and Comparative Example 1, the mechanical strength was evaluated, and the results are shown in Table 1 below.

TABLE 1

Example 1 Comparative Example 1 Mechanical Strength (Young's Modules) 50 MPa 70 MPa

In addition, for Example 1 and Comparative Example 1, the conductivity was measured by the 4-probe method (4-probe method) and the results are shown in Table 2. From the results in Table 2 below, it can be seen that the PBI material through the examples has greatly improved the ionic conductivity by using P ₂ O ₅ in excess.

TABLE 2

Example 1 Comparative Example 1 Ionic Conductivity 50 MPa 70 MPa

In addition, in Example 1 and Comparative Example 1, the fuel cell performance test was performed while flowing hydrogen and oxygen at 160 ° C. in a non-humidified state, and the results are shown in Table 3.

TABLE 3

Example 1 Comparative Example 1 Current value at 0.6 V voltage 1.3 A 1.0 A

As can be seen from the results of Table 3, in the case of Example 1 at the same voltage it can be seen that the battery characteristics are superior to Comparative Example 1.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

The present invention provides a polymer membrane for fuel cells that has increased molecular weight and is not harmful to the environment by a process of adding an excessive amount of dehydrating agent without using trifluoromethanesulphonic acid (CF ₃ SO ₃ H), which is very toxic when preparing a polymer. Can provide.

Claims (11)

It contains poly [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] polymer in the range of molecular weight 30,000-70,000, The polymer is A condensation reaction is carried out by adding a dehydrating agent comprising a 3,3′-diaminobenzidine monomer, an isophthalic acid monomer, and P ₂ O ₅ , and CH ₃ SO ₃ H to the reactor, A polymer membrane for a fuel cell which is prepared by adding an excess of P ₂ O ₅ to a reaction tank during the condensation reaction of the monomer. Condensation reaction of a 3,3'-diaminobenzidine monomer, an isophthalic acid monomer _, and a dehydrating agent comprising P ₂ O ₅ and CH ₃ SO ₃ H is added to the reactor; Preparing a polymer by adding an excess of P ₂ O ₅ to the reaction vessel during the condensation reaction of the monomer; Dissolving the polymer in an organic solvent; A method of manufacturing a polymer membrane for a fuel cell, comprising the step of casting and drying the dissolved polymer on a substrate. The method of claim 2, wherein the amount of P ₂ O ₅ is added in a molar ratio of 1: 5 to 7 times relative to the 3,3′-diaminobenzidine monomer. The method of claim 2, wherein the polycondensation reaction is performed for 30 minutes to 1 hour at a temperature of 160 ℃ to 170 ℃. The method of claim 2, wherein the polymer comprises a poly [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] polymer having a molecular weight in the range of 30,000 to 70,000. A catalyst layer formed by coating a catalyst slurry on one surface of an electrode support, wherein the catalyst slurry includes a polymer prepared according to any one of claims 2 to 5, and a metal catalyst supported on carbon. Battery electrode. The electrode of claim 6, wherein the catalyst layer has an ion conductivity of 0.06 S / cm to 0.08 S / cm. The electrode of claim 6, wherein the metal catalyst is platinum, ruthenium, or a mixed catalyst thereof. 7. The fuel cell electrode as claimed in claim 6, wherein the electrode support is a gas diffusion layer made of a conductive substrate. Anode and cathode electrodes located opposite each other; It comprises a high character film comprising a [2,2 '-(m-phenylene) -5,5'-bibenzimidazole] polymer having a molecular weight of 30,000 to 70,000 located between the anode electrode and the cathode electrode Membrane / electrode assembly; Including, A separator for sandwiching the membrane / electrode assembly; At least one electricity generating unit generating electricity through an electrochemical reaction between hydrogen and oxygen; A fuel supply unit supplying hydrogen to the electricity generation unit; And Oxygen supply unit for supplying oxygen to the electricity generating unit Including, The polymer is condensed by adding a 3,3'-diaminobenzidine monomer, an isophthalic acid monomer, and a dehydrating agent containing P ₂ O ₅ , and CH ₃ SO ₃ H to the reaction tank, and the condensation reaction of the monomer proceeds. A fuel cell system prepared by adding excess P ₂ O ₅ to the reactor. An anode electrode and a cathode electrode positioned opposite to each other, and [2,2 ′-(m-phenylene) -5 prepared according to any one of claims 2 to 5 positioned between the anode electrode and the cathode electrode; A membrane / electrode assembly comprising a polymer membrane comprising 5′-bibenzimidazole] (PBI) polymer; And a separator for sandwiching the membrane / electrode assembly, the at least one electricity generating unit generating electricity through an electrochemical reaction between hydrogen and oxygen; A fuel supply unit supplying hydrogen to the electricity generation unit; And Oxygen supply unit for supplying oxygen to the electricity generating unit Fuel cell system comprising a.

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